1. Field of the Invention
The invention relates to wheels of handcart and more particularly to a handcart caster.
2. Description of Related Art
The handcart is a pickup vehicle being pushed or pulled by human power, and it is the earliest ancestor of all kinds of vehicles. Although the continuous development of stuff-pickup technique of handcart, the handcart is still used till now as an indispensible pickup tool, mainly used in supermarkets, stores and production lines. The reason of wide using of handcart in producing and life is its cheap cost, easy maintenance, convenient operation, light weight and it can work in the places where the motor vehicles can not be used conveniently, and it is very convenient when the handcart is used to carry lighter stuffs in short distance.
The supermarket handcart has guiding, omni-directional or braking caster, and no matter it is guiding, omni-directional or braking caster, it includes bracket and rolling wheels set on the lower end of the bracket. And it is set flexible component on the joint of the bracket and the support shaft of the handcart. The flexible component mainly is rolling bearing, and no matter the caster with brake or the caster without brake, when the caster is installed on the handcart, and after the flexible component of caster and the support shaft are connected, if the axial directional orientation is not good or not firm, the handcart easily generated axial directional shake. So, in order to assure there is no axial directional shake happened or small shake range, the flexible component is needed to install firmly and has anti-shake effect itself.
In the Chinese patent publishing no. CN201291712Y, it is disclosed a kind of supermarket handcart caster. The handcart caster includes eccentric bracket component and rolling wheel component installed on the lower end of the eccentric bracket component, and it is set rolling bearing on the upper end of the eccentric bracket component, and the rolling bearing is connected with the support shaft of the handcart. As it is can be seen from the drawings of the publishing patent, the rolling bearing is deep groove ball bearing, and the steel balls are set single row in the bearing and the steel balls is linearly connected with the inner ring and outer ring of the bearing. When the axial directional shake of the support shaft of handcart happened, the linear connection of single-line steel balls and the inner ring and outer ring is extremely unstable, and the axial directional stress is smaller, and it is not suitable to carry heavy-duty cargos.
In the Chinese patent publishing no. CN201982492U, it is disclosed a kind of ball bearing used in handcart caster. The bearing includes inner axle with rollaway nest on its outer surface and steel balls rollingly set in the rollaway nest along the peripheral direction of the inner axle with the equivalent distance. The steel balls are single row balls and the steel balls are linear connected with inner ring and outer ring of the bearing. When the support shaft of the handcart generated axial directional shake, the linear connection of the single-row steel balls and the inner ring and outer ring is also extremely unstable.
Notwithstanding the prior art, the invention is neither taught nor rendered obvious thereby.